Abstract: The prediction of chemical stability of streptomycin sulfate solution is determined by linear non-isothermal method, and confirmed by classical isothermal method with the same batch of sample at pH 6.50. The activation energy of decomposition was found to be E=33 kcal·mol^-1 and 34 kcal·mol^-1 and the rate constant k_20℃=5.7×10^-6 h^-1 and 5.0×10^-6 h^-1, respectively by these two methods.